Fairlead for dragline excavators



Feb. 9 1926.

P. BURKE`4 FAIRLEAD FOR DRAGLINE EXCAVATORS Filed August 4, 1924 2 Sheets-Sheet 2 )N1/mfom gaan/5,09

ATTORNEYS Patented Feb. Q 1926.

'UNITED s'rA'rssfrA'ruuT oFFlcE.

PAUL BURKE, OF GREEN iBAY, WISCONSIN, ASSIGNOR TO N ORTHWS'I NGINEEBING COMPANY, GREEN BAY, WISCONSIN, A CORPORATION OF WISCONSIN.

A FAIRLEADFOR DRAGIJINE EXCVA'VATORS.

Application led August 4, 1924. Serial No. 730,068.

To all whom t may concern: l

Be itknown that I, PAUL BURKE, a citizen of the United States of America, and 4resident of'Green Bay, inthe county `of Brown and State of lVisconsin, have 1nvented new-and useful Improvements 'in Fairleads for Dragline Excavators, of which the following is a description, reference being had to the accompanying drawings,

which are a part of this specification.

The invention relates to tairleads for excavating machines, and more particularly vto fairleads for dragline excavators.

In operation, the bucket of a dragline eX- cavat-or is often displaced a considerable distance to one or the other side of the boom, which entails a corresponding lateral angulardisplacement of the portion of the drag cable between the fairleadand bucket with respect to the portion-lying between the drag drum and fairlead. operation must assume a large variety of positions in the vertical plane, there will be a vertical angular relative displacement of these two portions of the drag` cable. To absorb the lateral and verticalv components ot' the drag cable tension, resulting from the above displacement, -is the function of the fairlead. The types of fairlead in use today are so constructed that the contacts between the main drag cable and the sheaves or rollers oi the fairlead are 'principally rolling, such rolling, as against sliding contact,- being a necessary condition for satis- `factory cable lite. Unfortunately, however, these fairleads still leave a considerable source of cable wear, namely, in the lead of the cable between fairlead and drum, where, unless this lead issubstantially tangent to the helix formed by the last wrap of the cable, there may be and usually is side contact betweenthe loncoming or otgoing section of 'cable and the lasthprevious wrap,

with resultingI abrasion and wear.

Thus, the ideal condition would be to have the drag cable form, at all times, a straight line which is tangent to the helix from which the cable leads at the moment. No known tail-leads at the present time bring about this condition, and it is the object .of this invention to provide a 'fairlead capable of positively insuring that that portion of the drag cable lying between thc winding or draglxne drum and the airlead will be,at all times, nearly or substantially tangent to 'the drum.

Also, as the. bucket in the helix formed by the successive wraps of said cable about the cylindrical surface of The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings: Fig. l is an elevation view of an excavating machine equipped with the fairlead embodying the invention;

.Fig 2 is a detail plan view of the fairlead, drum'and inner end of the boom, parts being shown in section; i

Fig. 8 is an elevation view of themech- 'anism shown in Fig. 2;

Fig. 4 is a` detail sectionalview of part of the tairlead feed mechanism, taken on the line 4-4 of Fig. 3;

Fig. 5 is a detail sectional view taken on the line 5-5 of Fig. 4; Fig.,6 is a detail plan view of the feedscrew connection; i

Fig. 7 is a detail sectional view taken on the line 7-7 of Fig. 6.

Referring to Fig. 1, I have here 'shown a. dragline excavator equipped with'thetairlead embodying the invention, in which the numeral 8 designates the ytravellilngloase of the machine, here shown as provided with endless rotating base 10 mounted for turning thereon. The boom 11 is pivotally mounted at its lower end on the base l() and held in adjusted position by cables 12 connecting the outer end of the boom with the trame 13 of the machine. vThe hoisting drum 14 and the dragline drum 15 are suitably mounted on the base 10 and their shafts are providedrespectively with intermeshing gears 16 and 17, and the gear 16 meshes with a drive ,pinion 19 driven in any suitable manner from a' prime mover, not shown, on the base. Each of the drums 14 and 15 are also provided with clutches and brakes' to control their operation. A hoist line 20 leads from the drum 14 over a pulley 11 on the boom' ner to cause the bucket to perform its digpropelling treads 9, and having the:

, ging and unloading operations. Turning gear forthe base 10, of usual construction,

is also provided and is driven by the prime mover, not shown, on the base 10.

Referring to-Figs. 2 and '3, the dra-gline drum 15-s shown as grooved, which is preferred, though a plain surface drum may be used. The cable 22 is wound in by the rotation of the drum 15 through the drive from the gear -16 to the gear 17, and saidvdrum is providedwith a brake 23 of usual construction. Clutch mechanism, not shown', is provided for connecting. or disconnecting the drum 15 with its source of power.

Forward of the drum and mounted forl convenience upon the lower end of the boom 11 are two parallel stationary shafts 24 and 25 and respectively mounted'on these shafts, so that they may slide aswell 'as rotate thereon, are guide sheaves 26 and 27. Y. These sheaves are4 confined between -the parallel sides of a housing 28 also adapted to slide on the stationary guide shafts' 24 and 25.

. This housing 28 has sets of spaced arms 29 formed lipon its front, each set of which is bored to receive inclined pins'30 upon. which rollers 31 are mounted to rotate. The space between the #sheaves 26 and 27 and between the rollers 31 is such as to allow passage of the cable 22 therebetween, which is wound .at oneend on the drum- 15 and is secured in any'well-known manner to the bucket 21, as previously mentioned.

Secured to the drum- 15 and concentric with it, is a chain sprocket 32 connected by a chain 33 to a. sprocket 34 onthe shaft orv hinge-pin 3 5 of the boom. A Vsprocket .36 on' the shaft 35 is connected by a chain 37 to a sprocket 38 operatively connected with a lead or feed-screw 39. The double-chaindrive is here employed lbecause as a matter ,e of convenience the fairlead is mounted on-the boom. -It will, of course, be understood that when the fairlead, including the shafts 24 and .25, is mounted on a frame on the base 10 that only a single chain-drive vbetween the 'drum and the screw 39 would be'used.

The feed-screw 39 is preferably connected with the housing so as to permit some umversal play, as shown in Figs. 6 and 7 where the forked end 4() of said screw is loosely connected by a pin 41 with a lug 42- on the housing 28.- 1

`The preferred formof driving connection between the sprocket 38 and the screw 39 is shown in detail in Figs. 4. and 5, wherein the hub 43 of the sprocket is in the form of a sleeve journalled on lixed bearings 44 removably secured to-a fixed support'45' on. the boom, and the sprocket 38 drives the `nut 46 on the lead-screw 39 b v means of loosely-v fitting splines 47 and 48, respectively, on the hub of the sprocket and the nut 46, said nut being mounted between the vbearing members 44. This construction is of adlaterally on the shafts 24 and 25 under4 the action of the screw 39 whose nut 46 is rotated by the drive from the drum, and I so choose the relative numbers of teeth of the sprockets and the pitch of the thread on lthe lead-screw 39 that when the drum makes one revolution the lead-screw advances the housing 28 a distance equal to the axial pitch of the rope grooves on the drum or the thickness of the cable plus a slight amount of clearance when said grooves are not used. The hand of'the lead-screw is the same as that of the helix formed by the cable wrapped upon the drum. Thus, VI am able to maintain the run ofthe cable between theA fairlead and the drum nearly or substantially tangent to the helix formed by the last wrap of cableon the drum, thereby preventing the usual abrasion and wear of the cable.

By preference, thediameter and length of the drum are large enough so that it is unnecessary to use more than one layer of drag cable.- It is obvious that the initial adjustment being properly made so that the drag cable is substantially tangent to the helix vof the wrapped rope, that this relation will be maintained automatically whether the drum is wound full of rope, unwound empty, or in anv condition intermediate these two.

When the fairlead is mounted on the boom there is, of course, a slight relative rotation of the feed-shaft inadjustment of the boom angle, but inasmuch as the boom angle need be varied only within alimited range, it is obvious thatsuch variation in boom angle 'can cause only a neglible degree of error -in the lateral relationship between the airlead and the drumgrooves or wrapped ro e.

rom the foregoing Idescription it will he noted that VI- have provided a fairlead mechanism in which the run of the drag cable be tween the fairleadand drum is so guided as to prevent the usual wear due to the sliding contact of parts of said cable on each other as they pass off or are wound on said drum." f .y f-li I desire ittov .be understood that this invention is not `to' be limited to any specific' form or arrangement of parts except in so far as such limitations are specified in the claims or necessitated by the prior art.

What I .claim as my invention is: 1. In a machine, the combination with a supporting platform, of a winding drum mounted thereon, a boom pivot/ed at its lower end on said platform, .a fairlead mechanism including a reciprocating frame mounted on the lower end of the boom,`

line guide means carried by said frame, and means driven by the drum for moving said frame relative to the longitudinal axis of said drum to maintain the run of the line between said guide means and drum substantially tangent to the helix .formed by the previous wrap of line on the drum in any operating position of the boom relative to said platform. t ,t

V2. ln a machine, the combination with a winding drum and a line associated with said druml` of a fairleadmechanism including a reciprocating frame, line guide means carriedl bysaid frame, a feed-screw connected with said frame, Va nut on said feedscrew, and meansirotating in synchronisn'i with the drum and having a loose driving connection with -said initier turning said nut, Said feed-screw moving said frame. relative tothe longitudinal anis of the drum at a rate to maintaintherunof the line between said guide means and drum substanJ Atiailly tangentto the ,helix formedby the previous wrap et llineon said ditiml till? fili 3. ln a machine, theI comibinaationiA with a winding drum, a: line'assoeiated with said drain 'and a pivoted boom, of" af'ffairleadv mechanism including a' pair-of "stationary shafts mounted at they lower end lofthe boom adjacent its pivot, a frame slidablymounted on saidsha'fts, line guide meanscarried by said frame, a feed-screw connected with said frameE4 a nut for said feed-screw, a gear mounted in bearings on the boom and having aA splined connection with said mit, transmission mechanism between said gear and said frame including a drive from the drum to the hinge-pin of the boom7 and a drive from said hinge-pinto said gear, said transmission mechanism and feed-screw adapted to move said frame relative to the drum at arate to maintain the run of the line between said guide metins'and drum substantially tangent ,to the helix-forni-ed by the previous wrap of line 011 said drum.

'l. ln a machine, the combination with a winding drum, a line associated with said drum and a pivoted boom,"of a fail-lead vfeed-screw, a `gear mounted in bearings on `the boom and havingja splined connection with said nut,' transmission mechanism between said gear and saidy frame including a drive from the drum to the hinge-pin of the boom, and a'drive from said hinge-pin to said gear, said transmission mechanism and feed-screw adapted tomove. said frame relative tothe drum 'ata' rate'to maintain the runof the line between said guide means and drum substantiallyy tangentv tothe helix` formed by the previous wrap of line on said drum. -v

n a machine, the combination with a winding drum and a line associated with said drum, of 'a fairlead mechanism including-a reciprocating frame, a feed-screw connected with said frame, a mit on said feedscrew', a driving member having a loosely lsplined driving'- connection with said nut,

said feed-screw moving said frame relative to the longitudinal axis of the drum at a rate to maintain thne run of said line between `said guide means and drum substantially tangent tothe helix formed by the previous wrap of line Aon said drum.

'6. ln a dragline excavator, the combinan tion with the dragline drum and the daf-ag-l line, of 4a fairlead mechanism includ-ingv guide means movable relative. to the' longitudinal axis of the drum to guide the run of the cable between'the fairlead and the drum, and driving means between the drum and said guide means producing a positive ratio between the lateral displacement'of said guiding means and the angular displacement of the drag-drum about its anis' ture.

P UL BURKE.

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